Performance evaluation of community Based small scale irrigation schemes at Estie woreda, Amhara region, Ethiopia

Abstract

This study was conducted with the general objective of the performance evaluation of community based small-Scale Irrigation schemes at Estie woreda. In addition to water application, agronomic and economic performance evaluation, the study also assesses irrigation water management strategies adopted by the communities and identify the major challenges of community owned irrigation systems on selected three modern SSI structures namely Gomit, Gumara and Chena in the study area. Systematic sampling technique has used in sample size determination. Actual field investigation and measurements or survey works including simple observations of scheme at the sites were required to collect the necessary data to know the present condition of the scheme. These Primary data were collected from February to April. In addition, the collection of primary data which require questionnaires, Interview, Discussions with irrigation water users and other secondary data were carried out in June and July. Comparative analysis, use of software, Actual observation and onsite field evaluation of the sites were methods of analysis and evaluation used by this paper. Software like GIS Software, MsExcel, cropwat, surface irrigation software (SURDEV), Data collection instruments like GPS and Video camera, Soil data, Meteorological and Hydrological data for a site and basin, Design and feasibility documents of a site Flow Measuring Equipments were some of the materials used in this study. The flow discharges along canals in the study area were measured with floating method with 10cm width interval and the flow discharge at the field inlets were measured with buckets. After measurement of discharge at canal head and canal outlet, Conveyance efficiency of Gomit, Gumara and Chena were 63.83, 29.5 and 56.5 respectively. The application efficiency of Gomit, Chena and Gumara are 86.2%, 83.37% and 66.85%. Although those values of application efficiency are high enough, achievement of irrigation to the minimum infiltrated depth is poor in all schemes i.e. under irrigation is observed. Output per cropped area of Gumara, Gomit and Chena are 3.087, 4.68 and 3.95 respectively. The respective values output per command area of Gumara, Gomit and Chena are 3.19, 1.51 and 1.57 and the respective values output per irrigation supply are 10.05, 5.51 and 6.05 while output per unit water consumed of Gomit ,Gumara and Chena are 12.42, 7.69 and 9.99 respectively. Gomit irrigation project has highest output per cropped area (4.68) followed by Chena (3.95). The values of relative irrigation supply in Gumara, Gomit and Chena were 1.52, 2.68 and 1.96 respectively. The respective values of relative water supply of Gumara, Gomit and Chena were 2.08, 3.17 and 2.53. Gomit has highest value of relative water supply and relative irrigation supply. The water delivery capacity of the scheme shows the capacity of the main canal to convey the maximum peak consumptive demand. The water delivery capacity of Chena, Gomit and Gumara is 1.03, 1.46 and 0.54 respectively. The output of this paper shows that, without the water users association, the efficient irrigation scheme management is impossible. By strengthening the management capacity of water users association, legal and smooth handover of schemes after the construction, frequent evaluation and follow-up are critical to maintain sustainable performances of schemes.